velocityn.
/vᵻˈlɒsᵻti/, U.S. /vəˈlɑsədi/ 1.
a. Rapidity or celerity of motion; swiftness, speed.
ΘΚΠ
the world > movement > rate of motion > swiftness > [noun]
swiftnessc888
speedOE
swiftship?c1225
swifthead1340
speedfulnessc1386
quickness?a1425
hastinessc1425
speediheadc1450
swiftinessa1464
radeur1477
celerity1483
speediness1530
swithnessc1540
velocity1555
raptness1582
pernicity1592
rapidity1601
fastness1604
fleetness1625
rida1642
rapidness1650
mercuriousnessa1661
1555 R. Eden tr. G. F. de Oviedo y Valdés Summarie Gen. Hist. W. Indies in tr. Peter Martyr of Angleria Decades of Newe Worlde f. 188 This byrde..is of such velocitie and swyftnes in flying.
1575 J. Rolland Treat. Court Venus ii. f. 29v Thay bad him pas with all velocite. To the Gracis.
1607 E. Topsell Hist. Foure-footed Beastes 115 The Lybian Roes..(saith hee) are of an admirable velocity or swiftnes.
1646 Sir T. Browne Pseudodoxia Epidemica 235 Dolphins..Being the Hyeroglyphick of celerity,..men best expressed their velocity by incurvity, and under some figure of a bowe. View more context for this quotation
1661 J. Glanvill Vanity of Dogmatizing ix. 84 The supposed motion will be near a thousand miles an hour under the Equinoctial line; yet it will seem to have no Velocity to the sense.
1705 F. Fuller Medicina Gymnastica 16 His Blood flows with its due Velocity.
1789 H. L. Piozzi Observ. Journey France II. 370 Black heaths, and wild uncultivated plains, over which the unresisted wind sweeps with a velocity I never yet was witness to.
1803 W. Bingley Animal Biogr. III. 103 As considerable velocity is necessary to the animals composing the present class [sc. fish], their bodies are in general slender and thin.
1849 T. B. Macaulay Hist. Eng. I. iii. 379 The flying coaches are extolled as far superior to any similar vehicles ever known in the world. Their velocity is the subject of special commendation.
b. spec. Relative rapidity; rate of motion.
ΘΚΠ
the world > movement > rate of motion > [noun]
speedc1175
passa1393
pace?a1439
strake1558
rate1652
velocity1656
rapidity1701
rake1768
bat1824
clip1868
tempo1898
work rate1906
pacing1958
1656 tr. T. Hobbes Elements Philos. ii. viii. 82 Motion, in as much as a certain Length may in a certain Time be transmitted by it, is called Velocity or Swiftness: &c.
1715 tr. D. Gregory Elements Astron. I. i. §41. 91 The Velocity in A is to the Velocity in P, as SN to SH. But as the Velocities in A and P are, so are the Spaces run in the same time, by the Bodies.
1743 W. Emerson Doctr. Fluxions v It is the general Practice in Mechanics, to measure the Velocity of a Body by the Space uniformly described in given Time.
?1790 J. Imison School of Arts (ed. 2) 1 Mechanics is a science which treats of the forces, motions, velocities, and in general, of the actions of bodies upon one another.
1815 R. Bakewell Introd. Geol. (ed. 2) Pref. p. xvi In mechanics, the important question of the ratio between the velocity and momentum is still undecided.
1857 D. Livingstone Missionary Trav. S. Afr. xvi. 284 (note) A declivity of three inches per mile gives a velocity in a smooth straight channel of three miles an hour.
1880 S. Haughton Six Lect. Physical Geogr. iii. 137 It has..a velocity of upwards of three knots per hour.
c. In scientific use, speed together with the direction of travel, as a vector quantity.
ΘΚΠ
the world > movement > rate of motion > [noun] > in the physical sciences
celerity1734
velocity1847
the world > matter > physics > mechanics > dynamics > [noun] > speed or direction as vector quality
velocity1847
1847 Proc. Royal Irish Acad. 1845–7 3 345 We may always imagine a succession of straight lines, or vectors, to be drawn from some one point, as from a common origin, in such a manner as to represent, by their directions and lengths, the varying directions and degrees (or quantities) of the velocity of the moving point.
1873 J. C. Maxwell Treat. Electr. & Magnetism I. 9 The velocity of a body, its momentum,..an electric current,..are instances of vector quantities.
1883 Encycl. Brit. XV. 680/1 We are concerned only with what we may call the ‘speed’ of the motion. (We purposely avoid the use of the term ‘velocity’ here, because it properly includes direction as well as speed.)
1963 A. F. Abbott Ordinary Level Physics v. 50 In ordinary conversation the word ‘velocity’ is often used in place of speed. In science, however, it is important to distinguish between these two terms.
2.
a. Rapidity (absolute or relative) of operation or action; quickness.
ΘΚΠ
the world > action or operation > manner of action > rapidity or speed of action or operation > [noun]
celerity1483
speediness1530
navity1623
velocitya1674
expeditiousness1708
hot foot1869
a1674 Earl of Clarendon Brief View Leviathan (1676) 18 Mr. Hobbes..was with the velocity of a thought..able to decipher that impertinent Question.
1743 W. Emerson Doctr. Fluxions 2 He will find some to increase faster, others slower; and consequently that there are comparative Velocities (or Fluxions) of Increase during their Generation.
1794 J. Hutton Diss. Philos. Light 198 Neither the quantity of the fire, nor the velocity of its propagation.
1817 J. Mill Hist. Brit. India II. v. v. 479 Colonel Brathwaite was instructed to anticipate resistance by velocity of completion.
1858 J. A. Froude Hist. Eng. (ed. 2) IV. 481 The velocity with which the English world was swept into the New Era.
1871 B. Stewart Heat (ed. 2) §228 The rate at which it loses temperature or the velocity of cooling.
b. Economics. The rate at which notes and coins change hands; the rate of spending in an economy.
ΘΚΠ
society > trade and finance > management of money > expenditure > [noun] > rate of spending in economy
velocity1909
1909 I. Fisher in Jrnl. Royal Statist. Soc. 72 618 When we know statistically the velocity of circulation of money we shall be in a position to study inductively the ‘quality theory’ of money.
1911 I. Fisher Purchasing Power of Money ii. 17 Velocity of circulation, or rapidity of turnover, is simply the quotient obtained by dividing the total money payments for goods in the course of a year by the average amount of money in circulation by which these payments are effected.
1930 J. M. Keynes Treat. Money II. xxiv. 20 The expression ‘velocity (or rapidity) of circulation’ first came into use before the development of the cheque system... The ‘velocity’ measured the average frequency with which a loan (or a bank-note) changed hands.
1957 Economist 19 Oct. 209/1 The note issue is a good indicator because the velocity of notes, unlike that of deposits, is fairly steady.
1982 Chase Economic Observer Jan.–Feb. 3/1 Velocity, the rate of turnover of money, is typically measured as the ratio of GNP to the narrowly defined money stock.
Compounds
C1. General attributive.
velocity-measurer n.
ΘΚΠ
the world > movement > rate of motion > [noun] > in the physical sciences > measurement of > instrument
tachometer1810
velocimeter1842
velocity-measurer1850
tack1963
tacho1964
tach1966
the world > matter > physics > mechanics > dynamics > [noun] > speed or direction as vector quality > device to measure or record velocity
ballistic pendulum1764
tachometer1810
velocimeter1842
velocity-measurer1850
gun-pendulum1867
1850 J. Weale Rudim. Dict. Terms Archit. iv. 497/1 Such a velocity-measurer was constructed by Breguet, of Paris.
velocity ratio n.
ΚΠ
1887 D. A. Low Introd. Machine Drawing (1892) 36 Velocity Ratio in Belt Gearing.
C2.
velocity head n. [head n.1 44.] the velocity pressure of a fluid expressed in terms of the height from which the fluid would have to fall to attain the velocity exerting this pressure.
ΘΚΠ
the world > matter > physics > mechanics > force > [noun] > pressure > fluid pressure > specific
overpressure1819
head of steam1820
pressure head1856
velocity head1884
velocity pressure1904
impact pressure1919
impact head1928
1881 Encycl. Brit. XII. 462/2 v2/2g may be termed the head due to the velocity v.]
1884 A. Daniell Text-bk. Princ. Physics xi. 276 We may say that the velocity-head and the pressure-head are together equal to the total head.
1937 M. P. O'Brien & G. H. Hickox Appl. Fluid Mech. ix. 271 The true velocity head to be used in Bernoulli's equation is the average kinetic energy per unit weight of water flowing.
1979 A. L. Lydersen Fluid Flow & Heat Transfer i. 5 (caption) Pressure head (p/ρg) and velocity head (V2/2g) for frictionless flow from point 1 to point 2.
velocity microphone n. a microphone whose diaphragm is freely exposed to the air on both sides and so responds to the particle velocity within a sound wave rather than its pressure.
ΘΚΠ
the world > physical sensation > hearing and noise > audibility > sound magnification or reproduction > [noun] > microphone
carbon transmitter1878
microphone1878
carbon microphone1879
pantelephone1881
phonoscope1890
mike1911
condenser microphone1921
magnetophone1922
radio microphone1922
ionophone1924
crystal microphone1925
ribbon microphone1925
radio mike1926
laryngophone1927
velocity microphone1931
ribbon mike1933
pressure microphone1934
bug1936
eight ball1937
ribbon1937
throat microphone1937
throat mike1937
rifle microphone1938
parabolic microphone1939
lip microphone1941
intercept1942
spike mike1950
spy-mike1955
spy-microphone1960
mic1961
rifle mike1961
gun microphone1962
spike microphone1962
shotgun microphone1968
Lavallière1972
wire1973
sneaky1974
multi-mikes1990
1931 H. F. Olson in Jrnl. Soc. Motion Picture Engineers XVI. 695 The ribbon microphone..can therefore very appropriately be termed a ‘velocity microphone’.
1951 A. Sheingold Fund. Radio Communications xiii. 281 Velocity microphones may be designed to be unidirectional in their response.
1978 V. Capel Microphones in Action ii. 19 The polar diagram of a velocity microphone is different from anything we have discussed so far.
velocity potential n. [translating German geschwindigkeitspotential (H. von Helmholtz 1858, in Jrnl. f. die reine u. angewandte Math. LV. 25)] a scalar function of position such that its space derivatives at any point are the components of the fluid velocity at that point.
ΘΚΠ
the world > matter > physics > mechanics > dynamics > fluid dynamics > [noun] > irrotational flow > function
velocity potential1867
1867 P. G. Tait tr. Helmholtz in London, Edinb. & Dublin Philos. Mag. 33 485 In integrating the hydrodynamical equations, the assumption has been made that the components of the velocity of each element of the fluid in three directions at right angles to each other are the differential coefficients, with reference to the coordinates, of a definite function which we shall call the velocity-potential.
1878 W. K. Clifford Elem. Dynamic iii. 203 The circulation along any path from o to p..is called the velocity-potential at p.
1882 G. M. Minchin Uniplanar Kinematics 160 If..the velocity potential has at each point of the curve an assigned value.
1907 F. W. Lanchester Aerodynamics iii. 91 Fluid in irrotational motion has a velocity potential.
1937 S. L. Green Hydro- & Aero-dynamics ii. 19 When w = ϕ + iψ is a function of z = x + iy the conditions ϕx = ψy, ϕy = −ψx are satisfied, and these conditions are exactly the same as those satisfied by the velocity potential and the stream function for an irrotational motion in two dimensions.
1980 Bober & Kenyon Fluid Mech. ix. 417 The velocity potential, Φ, or the stream function, Ψ, are often introduced into fluid-flow problems because they frequently reduce the difficulty in obtaining a solution to a particular problem.
velocity pressure n. that part of the total pressure exerted by a fluid which is due to the velocity it possesses.
ΘΚΠ
the world > matter > physics > mechanics > force > [noun] > pressure > fluid pressure > specific
overpressure1819
head of steam1820
pressure head1856
velocity head1884
velocity pressure1904
impact pressure1919
impact head1928
1904 Inst. Mech. Engineers: Proc. Feb. 298 They used dry, clean air, and therefore it was possible to keep the Pitot tube extremely small, and to measure the static pressure in the close neighbourhood of the point at which the velocity pressure was measured.
1959 N. C. Harris Mod. Air Conditioning xv. 293 Velocity pressure is best measured by a Pitot tube combined with a draft gage which reads in inches of water.
1969 Oceanology IX. 585 The instrument is based on the measurement of the velocity pressure created by the wind.
This entry has not yet been fully updated (first published 1916; most recently modified version published online March 2022).
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